Revert of MD Downloads: track downloads in C++, dispatch discrete JS updates

chrome/browser/resources/md_downloads/action_service.js

Index: chrome/browser/resources/md_downloads/action_service.js
diff --git a/chrome/browser/resources/md_downloads/action_service.js b/chrome/browser/resources/md_downloads/action_service.js
index ee0a1b4a9fdc7384cfca8c7a120ddc7f6f18bf3b..f984fe5a14614e3b853993e4dcaad33b70577641 100644
--- a/chrome/browser/resources/md_downloads/action_service.js
+++ b/chrome/browser/resources/md_downloads/action_service.js
@@ -13,27 +13,6 @@
 
   /** @constructor */
   function ActionService() {}
-
-  /**
-   * @param {string} s
-   * @return {string} |s| without whitespace at the beginning or end.
-   */
-  function trim(s) { return s.trim(); }
-
-  /**
-   * @param {string|undefined} value
-   * @return {boolean} Whether |value| is truthy.
-   */
-  function truthy(value) { return !!value; }
-
-  /**
-   * @param {string} searchText Input typed by the user into a search box.
-   * @return {Array<string>} A list of terms extracted from |searchText|.
-   */
-  ActionService.splitTerms = function(searchText) {
-    // Split quoted terms (e.g., 'The "lazy" dog' => ['The', 'lazy', 'dog']).
-    return searchText.split(/"([^"]*)"/).map(trim).filter(truthy);
-  };
 
   ActionService.prototype = {
     /** @param {string} id ID of the download to cancel. */
@@ -61,15 +40,12 @@
     /** @param {string} id ID of the download that the user started dragging. */
     drag: chromeSendWithId('drag'),
 
-    /** @private {boolean} */
-    isSearching_: false,
-
     /**
      * @return {boolean} Whether the user is currently searching for downloads
      *     (i.e. has a non-empty search term).
      */
     isSearching: function() {
-      return this.isSearching_;
+      return this.searchText_.length > 0;
     },
 
     /** Opens the current local destination for downloads. */
@@ -102,10 +78,9 @@
 
       this.searchText_ = searchText;
 
-      var terms = ActionService.splitTerms(searchText);
-      this.isSearching_ = terms.length > 0;
-
-      chrome.send('getDownloads', terms);
+      // Split quoted terms (e.g., 'The "lazy" dog' => ['The', 'lazy', 'dog']).
+      function trim(s) { return s.trim(); }
+      chrome.send('getDownloads', searchText.split(/"([^"]*)"/).map(trim));
     },
 
     /**